Published: October 2015

You
have accepted a new patient for an initial pre-treatment consultation and
evaluation. You examined the child clinically and have seen only an initial
panoramic radiograph. In the discussion that followed, you have given the
parents an idea of what is likely to be involved in the treatment and have
informed them that the treatment plan will probably involve the extraction of
teeth. You have pointed out that sacrificing a tooth/teeth in this particular
case will be beneficial to the outcome of the case. In the language of chess,
this would be called a gambit. You have also pointed out to them that this is
only a tentative opinion, but that a definitive treatment plan would be
explained to them after you have seen plaster casts and additional relevant
radiographs, which together will enable you to make your diagnosis and
definitive treatment plan.

They
decide to go ahead and you arrange to obtain the needed casts and radiographs.
In your subsequent treatment plan, you decide that several teeth need to be
extracted – more than you first thought. Your receptionist calls the parent to
make an appointment for you to discuss the plan. The parent asks to speak with
you directly, with the view to discussing this in a telephone conversation
only, because they live at a considerable distance from the office and it is
not easy for them to come. Their real argument is that since you will only be
talking and active treatment will not be started at that visit, could you not
just provide them with the referral for the extractions. Should you accede to
their wishes, you may well spend the next 15 minutes giving them the needed
objective criteria on which your decision is based, in the hope that they might
understand the finer points that brought you to this decision, in the absence
of visual aids of any sort. The chances are that they will not understand
and you then stand a good chance of losing the patient. Assuming your
assessment and operative intentions are correct, their decision not to accept
your advice can be interpreted as being harmful to the patient. Thus, with the
best intentions of both sides, appropriate treatment will have been rejected.

Subjectively,
the child does not want teeth to be pulled and neither do the parents. For that
matter, you are also in principle against the extraction of healthy teeth.
Neither you nor the parents can be sure how the overall experience of
extractions will affect the child’s psyche and his/her attitude to dentistry
thereafter. So, there is a built-in reticence when it comes to the extraction
of healthy teeth, permanent or deciduous. Objectively, however, its performance
was necessary to prevent damage and/or to provide benefit. Let us discuss 3
specific cases.

Patient
#1

The
initial records of the patient were sent to me in October 2012, when she was 9
years of age. The orthodontist in the U.K. requested an opinion because her
unerupted maxillary canines appeared to be in locations and at angles which he
suspected would not presage normal eruption. He wondered whether the
extraction of deciduous canines might be advantageous in improving the chances.
The reason for the referral to me was that the child’s mother, a physician, is
my niece and, in her own field, she has a minimum interventionist attitude. She
was not at all happy about the possible need to extract teeth.

Fig. 1a. A panoramic view of patient #1 and of poor
quality, taken at age 9 years. The film
shows the mesially displaced and unerupted permanent canines displaced,
superimposed on the apical areas of the roots of the lateral incisors.

The
quality of the October 2012 panoramic view (Fig. 1a) was poor but it provided sufficient
information for me to offer an opinion. The
permanent incisors and first molars were the only erupted permanent teeth in
both jaws. I noted that all the permanent teeth could be seen in their various
stage of development on the film, including third molars and I assessed her
dental age at about 8.5 - 9 years, on the basis of the degree of development of
root length and apex closure.1-3
Aside from the right deciduous maxillary first molar which had been extracted
due to caries some time earlier, the deciduous molars and canines were all
present in the mouth. The unerupted permanent maxillary canines were high up in
the maxilla, close to the apices of the lateral incisors and with a
mesio-angular orientation, particularly on the right side. The roots of the neighbouring
maxillary deciduous canine showed virtually no sign of resorption. At the time
I supported the decision to extract the deciduous canines, but I also requested
the extraction of the left first deciduous molar, in line with the findings of
the study of Alessandri Bonetti et al.4.In my e-mail reply to the
orthodontist (with copy to mother) in regard to the right canine, I noted “…. this step should reduce
the chances of canine impaction from "highly likely" to just
"likely", but I think it is worth the gamble.”

Fig. 1b. Clinical intraoral views of the teeth in
occlusion at age 12.10 years, showing inadequate space for the unerupted
maxillary canines.

Fig. 1c. The panoramic view at age 12.10 years.The permanent teeth are denoted in blue and the deciduous
teeth in red. Note the advanced state of calcification of the roots of all the
unerupted permanent teeth compatible with a dental age of about 12 years.

Fast forward to July 2015: I was
again called into the decision-making process for my great-niece almost 3 years
later and at age 12.10 years. Clinical photographs (Fig. 1b) and the new panoramic film (Fig. 1c)
showed that there were still 6 deciduous teeth in the mouth. The left permanent
canine had improved its position and direction and appeared likely to erupt
normally if space were made for it, but the right canine had not significantly
altered its position and must accordingly be re-defined as impacted.

We had clearly lost the gamble of the extraction of the deciduous canines and its hoped-for
effect on the right permanent canine! However, I disagreed with the
orthodontist’s expressed view that dental development was delayed, despite the
presence of 6 deciduous teeth. I pointed out that the root development of the
premolars, canines and lower second molars was well advanced and this would put
her dental age at almost the same as her chronologic age. In other words, the
deciduous teeth must be re-defined as over-retained and impeding the eruptive
progress of the normally-developing premolars. The maxillary first premolars were
apparently rotated mesio-buccally and I would not have been surprised to see on
a CBCT that the palatal root apex impinged on the unerupted right canine. The
lower second molars, with most of the roots completed, were uncharacteristically
low down in the bone.

The biggest problem
at this time was resolving the impaction of the right maxillary canine. To
diagnose its exact position, a cone beam CT was certainly indicated. However,
this important diagnostic step was deliberately delayed until the surgical
resolution of the dentigerous cyst. The treatment advice given was follows:-

2. place an upper transpalatal bar soldered to molars band, extract
the 2 upper deciduous molars and push the first premolars distally to create
excess space for the canines. In so doing, I was intentionally recommending to temporarily crowd out the
second premolars. This I advised on the basis that the second premolars will
almost always erupt later without a problem when space is re-opened for them.

3. distally upright and mesio-lingually rotate the first
premolars to thereby distance the palatal root from the canine and provide the
canine with space. This would hopefully encourage the ectopic tooth to start on
a downward path.

4. repeat the panoramic radiograph and, if no positive autonomous progress was seen, to opt for surgical exposure. It
would be at this point and under these circumstances that a CBCT will likely be
needed to evaluate the exact location of the canine, whereas I considered it
unnecessary until this point.

5. on the same panoramic view, the lower second molars should be
reviewed.

Because of the possibility of close proximity of the right canine
#13 to the mesially tipped root of the lateral incisor (to be assessed on the
CBCT), it would be important not to distally upright this tooth with initial leveling
and aligning wires until the canine is distanced - for fear of clashing and resorbing
the incisor root. The orthodontist must be aware that a light archwire in a
normally-placed edgewise bracket would upright the incisor rapidly and bring it
into ill-advised contact with the canine.

So, the alternatives would be:-

a. not placing a bracket on the lateral incisor until much
later, when the later panoramic view evaluation indicated an improved position
and distancing of the canine, vis-a-vis the root of the incisor

b. placing a vertically-oriented eyelet and thread the archwire
through it - no uprighting possible – and replacing it later with a regular
bracket when the canine improves.

c. placing a bracket at an initially abnormal angle that will
not upright the tooth - rebonding later

d. placing a Tip Edge bracket, whose very wide beveled slot affords
this leeway and later add an auxiliary uprighting spring or re-siting the
bracket

Mother and father were copied into
this e-mail recommendation and mother’s comment was “….I’m a bit taken
aback” and “…. It all sounds rather extensive and invasive” and “…..Surgical
exposure of the canine?” and “… How many teeth would need to be extracted?” and, finally,
“…… we need to speak face to face!” There was obviously a crucial need
for a comprehensive explanation.

In preparation for the upcoming
discussion, I annotated the panoramic view by labeling the individual teeth on
a Power Point presentation, using the easily understandable Federation
Dentaire Internationale (FDI) tooth numbering system and this served as an
important and graphic visual aid to the explanation. I requested that the parents study it so
that we could use this as the basis for a Skype discussion across several
thousand miles of cyberspace.

Both parents were highly objective and
availed themselves of the opportunity to ask all the important and relevant
questions, including the implications of no treatment or alternative treatment.
A face-to-face meeting would have been preferable by far but, at the end, they
gave their informed consent and accepted the proposed treatment plan.

It is not a comfortable position to be in
when long distance advice is sought by parents who are who are family members.
However, the orthodontist who had been consulted and who will undertake the
treatment, is entirely competent, well qualified and highly respected.

Patient#2 -Just deciduous teeth

One of the most important principles
associated with Serial Extractions, as an orthodontic treatment modality and as
first described in 1929 by Kjellgren5in Sweden, is
that extraction of the first deciduous molar at 8-9 years accelerates the
eruption of the first premolar, in order that the premolar may be extracted as
soon as it erupts and, in any case, well in advance of the eruption of the canine.
In crowded cases, the intrabony position of the premolars appears to cause the
canine to adopt a more mesial position than is normal. Thus, extraction of the
first premolar is a logical step to permitting the canine to autonomously drop
back distally into the organizing and repairing premolar socket.

Alessandri Bonetti and co-workers in
Bologna, Italy, have recognized that accelerating the eruption of the premolar
by extraction of the deciduous molar, at the same time as extracting the
deciduous canine offers this advantage even when the premolar is not extracted.
The logic is as follows:- as the premolar migrates downward in the maxilla, its
crown moves vertically downward and away from the crown of the canine. The canine then comes into a mesio-distal
relationship with the much narrower cervical and root areas of the premolar,
which will provide the canine with a little extra space on the distal. In their
randomized clinical trial, the Bologna team found that spontaneous eruption of
the permanent canine occurred much more frequently than when only the deciduous
canine was extracted.

In the mandibular dentition, the
difference in time lag between the permanent canine and the first premolar is
very small and often the canine will erupt first. Thus, the attempt to
accelerate premolar eruption rarely has the same beneficial effect as in the
maxilla.

The mother of the child in this second
case had been treated by me as a young teenager and had regarded it as a very
positive experience, which was why she now brought her daughter to see me. She
trusted my judgment implicitly, she had said.

Fig. 2a & 2b. Intra-oral view of the teeth in
occlusion and occlusal views of patient #2 showing the marked degree of
anterior crowding in both jaws.

Fig. 2c. The panoramic view on the basis of which it was
decided to advise the extraction of the maxillary deciduous canines and
deciduous first molars. Extraction of mandibular deciduous teeth was considered
non-essential at this time.

The daughter’s dentition (Fig. 2a-c) was in an early
mixed dentition stage with antero-posteriorly normally-related teeth in the
posterior segments and the first
permanent molars ideally placed. The maxilla was narrow and the deciduous
molars were in crossbite on each side. There was a wide median maxillary
diastema and the lateral incisors had erupted into lingual crossbite. The
central incisors featured a normal overbite and overjet and there was
considerable crowding of the incisors in both jaws.

The phase 1 treatment advised was the
extraction of the deciduous maxillary canines and first molars only. This was
to be followed by correction of the incisor crossbite using a simple removable
acrylic plate carrying springs aimed at tipping the lateral incisors over the
bite. No treatment was offered in the mandibular arch, although extraction of
the deciduous canines might have been expected to achieve some alleviation of
the crowding. Further treatment was envisaged in phase 2 for the resolution of
the remaining and potential future problems that may occur following the
eruption of the premolars and canines.

The treatment plan was kept simple and
mother requested being informed in a telephone conversation, since it would
otherwise require her to take off time from her important work as a prominent
lawyer in the Law Courts. Given the fact that 4 deciduous teeth needed to be
extracted, it was felt that there would be a better chance of the parent understanding
the reasons for the multiple extractions in a face-to-face meeting. Thus, an
appointment was scheduled at the office in order to explain the treatment
proposal, using the plaster casts and radiographs as visual aids. I considered
that informed consent could only be effectively elicited in this way.

Mother later confirmed that she would not
have been prepared to accept this treatment verdict on the basis of the
telephone call that she had earlier requested and I would not have been able to
provide the child with the full benefit that the plan had to offer. So much for
“trusting my judgment implicitly”!

This 12 year old girl had been seen by a
trained orthodontist and by an oral and maxillofacial surgeon, both of whom
felt that the maxillary right canine impaction was particularly difficult and
was additionally complicated by a marked degree of generalized crowding. They
both considered that the canine should be extracted. The parents were not happy
with this advice. Under these circumstances and because of my special interest
in the treatment of impacted teeth, the orthodontist decided to refer the case
to me for advice and treatment.

Fig. 3a. Clinical intra-oral views of the teeth of
patient #3. These poorly taken photographs accompanied the patient on her first
visit.

Fig. 3b. Intra-oral occlusal views of patient #3

.

Fig. 3c. The panoramic view shows the extreme
displacement and horizontal orientation of the canine, with an outline of the
dentigerous cyst. It also shows the unresorbed mesial root of the mandibular
right deciduous second molar, an enlarged dental follicle at tooth #23 and
generally advanced calcification of the unerupted premolars and canines. The
mesially impacting second permanent mandibular molars can be seen, together
with the congenital absence of 3 of the third molars.

Fig. 3d. The lateral skull view shows the maxillary right canine located very high in the maxilla and surrounded by a dentigerous cyst, as can be more clearly seen in the parallel CBCT view.

I examined the patient with the view to
evaluating the whole dentition and the overall malocclusion. I then used the
existing panoramic radiographic and subsequently performed CBCT images to
diagnose the location and relations of the impacted tooth

Much more detailed information is available on the CBCT 3D video clip and on the at the following URL's

https://youtu.be/WAcmIHbLTQ8 Click on this link or
paste to your browser to see this video and how it reveals important 3D
information of the exact location of the canine in relation to the surrounding
teeth and bony structures. Note the enlarged follicle/dentigerous cyst.

https://youtu.be/RkupK7-wX5c Click on
this link or paste to your browser to see this video.This multiplanar reconstruction provides
serial cuts in one plane, with reference lines to show their exact location in
the other 2 planes of space.

Following this, I
tried to find a reason why the tooth had become impacted. My findings were as
follows:-

Angle’s class 2 division 1 subdivision,
with a full class 2 relationship on the right side. The overjet was 8.5mm and
the overbite incomplete due to a forward tongue posture during swallowing and
speech.

The deciduous canines and deciduous second
molars in the maxilla were still present, together with the right mandibular
second deciduous molar. A lower dental midline discrepancy of 5mms had resulted
in the blocking out of the unerupted, palpable, right canine. This tooth could
be palpated high in the vestibulum above the lateral incisor. The teeth in
general were large and there was a marked degree of crowding in both jaws. A
recent panoramic film was the only radiograph that was initially available and
it showed a full complement of permanent teeth, with the exception of the right
side third molars. It also confirmed the extreme vertical location and
horizontal orientation of the maxillary right canine, high above the reflection
of the vestibular mucosa, under the nose and at the level of the anterior nasal
spine. The tooth was encompassed by a much enlarged dental follicle/dentigerous
cyst. It could also be seen that the adjacent deciduous canine had an almost
complete root, exhibiting no resorption. The mandibular permanent second molars
were unerupted and mesially tipped, mildly impacting against the distal bulge
of the first permanent molars.

Given the child’s mild bimaxillary
protrusion, together with the crowding of her large teeth anteriorly and
posteriorly, she was clearly a candidate for a 4 unit extraction procedure –
but which 4 and what about the 5 retained deciduous teeth?

With the class 2 relation and the
enlarged overjet, the natural choice for mandibular extraction was the second
premolar on the right side. On left side, the first premolar was chosen to
enable a swift resolution of the midline discrepancy.

The difficult decision came in regard to
the right side of the maxilla. If the first premolar were to be sacrificed on
the right side, we would then need to deal with a large cystic lesion and a
very difficult canine impaction, both in terms of the biomechanics and the
post-treatment periodontal prognosis. There was no question that the chances of
a technically successful reduction of the impaction and ideal orthodontic
alignment were very high, with a good degree of spontaneous positional
improvement likely, following the elimination of the cyst. However, the projected
outcome would leave the patient with a canine which had increased crown length
and the strong possibility of an oral mucosa attachment on the labial side,
rather than attached gingiva.

The temptation to plan to realign the
canine at the expense of the first premolar might be considered by some
orthodontists to be one of the signs of their “passage to manhood”. The fact
that another orthodontist and an oral and maxillofacial surgeon had recommended
the opposite might be further encouragement for him (not usually her) to go for
it. This is likely to be more for the orthodontist’s macho prowess than for the
patient’s benefit.

The 5 deciduous teeth were still in place
because the two maxillary second premolars were mildly lingually inclined and
the mandibular second premolar was resorbing only the distal root of the
deciduous molar. Dental crowding had slowed down the eruption of the left
canine, leaving the deciduous canine relatively undisturbed and its antimere was
similarly unaffected because of the displaced right permanent canine in
question. Each of the successor permanent teeth had more than 2/3 of their
final root length, which therefore determined that the 5 deciduous teeth were
over-retained.

Appliance therapy should be initiated in
the mandibular dentition immediately following the extractions, to move the
dental midline to the left and to create space for the spontaneous eruption of
the right canine.

In the maxilla and assuming that the
choice for extraction on the right side would be the canine itself, then
appliance therapy would begin immediately and among its other functions, it would
be aimed at relocating the first premolar into the canine site. If the preference
of the orthodontist would be to extract the premolar, then exposure of the
canine should not be undertaken at least until several months have elapsed
following the extractions, in order to permit the patient to benefit from a
potentially considerable degree of spontaneous reduction of the displacement of
the canine that is likely to occur with elimination of the dentigerous cyst. In
this case, a maxillary holding device would be needed to prevent molar drifting
and space loss.

It is at this point that I was in a position
to speak with the parents and child, to deliver the verdict that 4 permanent
and 5 deciduous teeth need to be extracted as an intrinsic part of the
orthodontic treatment! This type of consultation session could last anything
from 15 to 45 minutes of my valuable time, depending on the parents’ level of
understanding and sophistication and on my mode of presentation of the facts
and the plans for treatment. Visual aids were essential and began with the
plaster casts, the panoramic film and an annotated tracing of the film. These were
then followed up with a few 3D screen shots and a 3D video clip movie to
enhance the parents’ and child’s understanding.

The preparation for the meeting was
time-consuming, but successfully achieved its intended outcome and the patient
was referred to have her 9 teeth extracted as the first step in her treatment.